Problem: If $x \triangleright y = 4x^{2}+y^{2}$ and $x \otimes y = (6-x)(y)$, find $6 \otimes (-1 \triangleright -1)$.
Explanation: First, find $-1 \triangleright -1$ $ -1 \triangleright -1 = 4(-1)^{2}+(-1)^{2}$ $ \hphantom{-1 \triangleright -1} = 5$ Now, find $6 \otimes 5$ $ 6 \otimes 5 = (6-6)(5)$ $ \hphantom{6 \otimes 5} = 0$.